One of the numerous techniques in existence for performing the cataract operation, consists in extracting the lens material from the capsular bag after making a circular opening in the anterior wall of the bag (capsulorhexis). The preserved portion of the capsular bag then comprises the posterior wall and a ring of the anterior wall connected to the posterior wall by the equatorial wall of the bag which co-operates with the ciliary muscle via the zonular fibers.
After this lens material has been extracted, artificial lens (an implant) is generally installed in what remains of the capsular bag, the artificial lens comprising a central optical portion fitted with so-called "haptic" portions which serve to hold the optical portion in the capsular bag by bearing against the inside face of the equatorial zone of the capsular bag.
These haptic portions can be of numerous shapes. Among the most common, mention is made of resilient loops which extend radially from the optical portion and then curve so as to present respective relatively long portions that bear resiliently against the inside diameter of the capsular bag. Others are formed by radial arms that are regularly distributed around the optical portion and that terminate in respective outer swellings in the form of circular arcs that bear against the equatorial zone of the bag.
It is known that the presence of the epithelial cells which line the inside surface of the capsular bag in the equatorial zone gives rise to cell growth inside the bag, which growth is referred to as fibrosis. This fibrosis differs very widely from one subject to another and its extent can be estimated by the surgeon during a clinical examination of the patient. In general, it occurs to a greater extent in the equatorial zone of the bag where the germinal cells are located.
One of the consequences of this fibrosis lies in the dislocation or progressive expulsion of the implant from the capsular bag. One of the qualities that an implant needs to present thus lies in its ability to accommodate such fibrosis either in order to limit it or else in order to take advantage of it so as to secure the implant better in the capsular bag.